Left Lane Capital and First Round Capital led the round. Brellium says CortexLM checks every patient note against each provider’s own requirements.
Key Takeaways
- Audit pressure on providers keeps widening. HHS launched an AI-driven audit initiative in May, and CMS handed states a 173-page ABA oversight toolkit in August.
- Brellium raised $23 million to expand its AI clinical compliance platform. Left Lane Capital and First Round Capital led the round, which will fund a move into cardiology, pain management, and primary care.
- CortexLM audits every patient note before a claim goes out. Brellium says it has reviewed 22 million visits and protected nearly $2 billion from recoupment, figures that come from the company.
- Brellium’s ABA checks mirror what federal auditors found. Its criteria flag sleep references and missing co-signatures in ABA session notes, and OIG’s state audits cited similar documentation gaps.
Zach Rosen started Brellium after a misdiagnosis that, he later learned, could have been avoided had a few boxes in his medical chart been checked, as Fierce Healthcare reported when the company raised its Series A. The New York company he co-founded now sells software that reads clinical documentation for exactly that kind of gap.
On Tuesday, Brellium said it had raised $23 million in venture funding and introduced CortexLM, a system it describes as reading every patient note and proposing fixes to care and documentation before billing. Left Lane Capital and First Round Capital led the round, with participation from Digital Health Venture Partners, according to the announcement and a LinkedIn post by Rosen. Axios also reported the raise. Brellium did not disclose a valuation.
Brellium’s $23 Million Round: Left Lane Capital and First Round Capital Return
Both lead investors also led Brellium’s $16.7 million Series A in April 2025. Henry Toole, a Partner at Left Lane, said in the announcement that the firm invested again because of the team’s execution. Compliance may lack glamour, he added, but much of the market rests on it. The round follows other recent investments in behavioral health software, including Hi Rasmus’s $50 million raise in September.
The new money will fund expansion into cardiology, pain management, and primary care, along with deeper work in the revenue cycle, the company said. Brellium reports more than 215,000 providers and 200 provider groups across all 50 states, including Gentiva, Maxim Healthcare, Rula, and Headspace. It says Headspace went from reviewing 2 percent of therapy notes to 100 percent, and it offers to cover the cost if CMS or a payer finds a problem in a chart Brellium has already cleared.
CortexLM and ABA Session Note Compliance
ABA has been part of the business for years. Brellium publishes case studies from providers including Compass ABA and Full Spectrum ABA, and a June update to its audit criteria added checks for ABA notes that mention a client napping or sleeping during direct treatment, citing audits and media reports about billing for non-therapeutic time. The company said 9 percent of notes were flagged for such references in October 2025. The same update added a check for supervising Board Certified Behavior Analyst co-signatures on 97153 notes, following what Brellium described as a 2024 Anthem reimbursement policy in nine states.
Those categories track with federal findings. In the four published OIG audits of state Medicaid ABA programs, auditors cited missing parental signatures, identical notes across clients, and records of children napping during billed sessions. Wisconsin, the second state in the series, is still working through OIG’s recommendations. The rules behind those checks will also shift on January 1, when the 2027 CPT code set adds six adaptive behavior codes and splits 97155.
Medicaid ABA Audits and Payer Scrutiny Behind Brellium’s Raise
“Providers and payers have been stuck fighting the same fraud, waste and abuse problem from opposite sides of the table for years,” Rosen said in the announcement. That scrutiny has widened in 2026. HHS launched its AERO initiative in May, using AI tools to review at least five years of audit history across all 50 states. In August, CMS released a 173-page ABA toolkit for state agencies, reporting that Medicaid and CHIP spending on ABA rose 421 percent from 2021 to 2025. States have tightened oversight on their own as well, from North Carolina’s plan-led fraud task force to Florida’s utilization controls.
